Exhaust manifold



Feb. 16, 1932. M, BELLANCA 1,845,474

EXHAUST MANIFOLD Filed Feb. 21. 1930 Qwuentoz Patented Feb. 16, 1932UNITED STATES PATENT OFFICE Application filed February 21, 1930. SerialNo. 430,379.

This invention relates to the construction and mounting of an exhaustmanifold for aeronautical engines.

In the development of airplanes in connection with which engines of theradial and other more or less similar types are used, considerabledifiiculty has been found in so mounting the exhaust manifold that itwill not present a substantial surface area to produce air resistanceand a corresponding restriction in speed of flight of the airplane. Thisdifiiculty arises out of the necessity for mounting the exhaust manifoldoutside the chamber formed by the shell of 13 the fuselage and in adisposition substantially encircling the cowl portion of the fuselagetransversely to the direction of flight. The manifold by thus extendingacross the line of flight, presents its forward surface to throughoutits length to the resistance of the It has also beenfound that when theexhaust manifold is mounted to the rear of the engine cylinders, as isordinarily done, hot

2.5 spots develop along the manifold opposite each of the cylinders.This is due to the fact that the cylinders shield these spots from thefull effect of the cooling air and that some of the heat from thecylinders themselves is transmitted to the manifold at these points.

A general object of the present invention is to provide an exhaustmanifold for radial aeronautical engines which will be free from theobjectionable features referred to and which will provide a minmumamount of air resistance.

I Further objects of the invention are to minimize the effects of thenoise produced by the discharging exhaust, to prevent overheating of themanifold either wholly or in spots, and to prevent buckling ordistortion of the parts under expansion effects arising out oftemperature changes.

The invention includes the mounting of the exhaust manifold in a recessor channel formed in the surface of the engine cowling, the manifoldbeing thereby partly or wholly protected from engagement of the rushingair therewith.

Another feature of the invention is the mounting of the manifold in aspaced apart relation to the surface of the receiving channel so thatair can flow through the space between the manifold and channel surfaceto produce a cooling effect on the manifold and prevent overheatingthereof.

Another feautre of the invention is that the manifold is allowed toproject slightly outside of the surface of the cowling so as tointercept a part of the air current and direct it through the spacebetween the manifold and the channel surface.

Another feature of the invention resides in the positioning of themanifold to the fore of the engine cylinders instead of to the rearifnlgrder to avoid heat spots on the mani- Another feature of theinvention resides n the provision of an exhaust manifold having aformation in cross-section such as will provide a minimum air-resistancearea.

Another feature of the invention resides in the use of flexible jointsin the manifold structure to prevent injury to the parts by 7 expansionand contraction effects.

Still another feature of the invention resides in an adaptability of themanifold structure to be mounted in various positions to cause theexhaust to be discharged at any desired point in the length of themanifold structure.

Other features of the invention will be hereinafter referred to.

In the drawings, in which a preferred embodiment of the invention hasvbeen selected for illustration, 4

Figure 1 is a diagrammatic view showing a portion of the forward endofan airplane equipped with an exhaust manifold construction embodying theinvention.

Figure 2 is a sectional view on an enlarged scale taken on the line 22of Figure 1.

Figure 3 is a detail perspective view of the 95 telescoping expansionjoint employed in my improved manifold.

Figure 4 is a detail perspective view of the flexible joint employed inthe branches of my improved manifold. 1 0

Figure 5 is'a sectional view of a modification of Figure 2.

Referring to the drawings for a more detailed description of theinvention, at is shown the engine cowling portion of the fuselage of anairplane throu h openings 11 in which the cylinders 12 of an engine ofthe radial type protrude. The forward portion of the cowling 10 isequipped with a cap member or fairing 13 designated to decrease theefiect of air resistance acting on the hub portions of the propeller14:-

In order to dispose of the exhaustfrom the radiallydisposed cylinders 12through a common discharge conduit an exhaust manifold 15 is made use ofwhich is disposed in a substantially encircling relation to the cowlstructure 10, the location of the manifold being just to the fore of thepositions of the engine cylinders 12. Branches 8 are provided atintervals along the exhaust mam-- fold 15 for the purpose of receivinginto the manifold the exhaust from the respective cylinders. Each ofthese branches is joined to a pipe connection 16 by a flexible jomt 22,shown in detail in Figure 4. One the free end of each of the pipeconnections 16 is provided a coupling member 7 whereby members 16 aretightly secured to the discharge ports 17.

In order to provide for expansion or construction of the manifoldstructure itself under changing temperature conditions, a telescopicjoint 25, such as is shown in Figure 3, is provided, which permits ofrelative movement of the contiguous sections of the manifold toward orfrom each other to thereby prevent distortion or other injury to themanifold by the expansion and contraction effects due to changes intemperature.

In order to cause the manifold to present a minimum area of surface toprevent air re-'- sistance the manifold is mounted in a recess or groove19 formed in the outer surface of the engine cowling 10. The groove orrecess 19 extends circumferentia-lly around the entire surface of thecowl and the disposition of the groove provides for the mounting of themanifold. 15 in any desired angular relation to the cowl so as to causethe discharge member 18 tobelocated at themost convenient point. InFigure 1 of the drawings the discharge member 18 of the manifold isshown disposed beneath the floor wall of the fuselage, this location ofthe discharge terminal being useful in overcoming the effect of noisesproduced by the exhaust on the occupants of the compartments in thefuselage. It will be clear that the manifold 15 may be rotatablyadjusted within the groove 19 to cause the terminal discharging member18 to be disposed along either side of the fuselage or at a. point todischarge above the fuselage and the supporting wing or plane.

In order to prevent overheating of the manifold and the communication ofheat to the adjacent surface of the cowl 10, the manifold 15 is somounted that its inner wall 29 is slightl spaced apart from the adjacentsurface of the groove or recess 19 as is clearly shown in Figure 2 ofthe drawings. The space'20 which is thus formed provides a passagewaythrough which air can fiow, as is indicated by the arrowsin Figure 2 ofthe. drawings, to thereb dissipate heat and pre vent overheating o theadjacent parts. In order to facilitate the rush of air through thepassageway20 formed between the manifold 15 and the surface of thegroove 19 the forward or leading edge of the manifold is caused toprotrude slightly beyond the adjacent outer surface of the cowl 10 to'thereby function to provide a scooping action on the air stream rushingrearwardly along the surface of the cowl 10. The air thus caught orentrapped is diverted through the channel 20 as will be seen andproduces the cooling efi'ect referred to.

It will also be noted that the cross-section or formation of themanifold member 15 is such as to present a minimum degree of resistanceto the air. In the drawings it will be noted that the manifold has theformation of a flattened tube with forwardly and rearwardly extendingangles and a substantially fiat outer surface 21 following approximatelythe contour of the outer surface of the cowl 10. While this particularformation has been found effective in practice it will be apparent thatother formations of the manifold cross-section may be employed withuseful results.

Another feature of the invention resides in the use of flexible oryielding coupling elements in the body structure of the manifold memberand also in the pipes 16 through which connections are made between themanifold and the engine cylinders'12. Coupling members or joints 22 areprovided in the pipe connections 16 for the purpose. These couplingmembers may take the form of split sleeves an example of which is shownin Figure 4 of the drawings, the sleeve being provided with a clampingbolt 23 and having suitable corrugations 24 to prevent slipping of thecouphng member from engagement with the joint sections of the exhaustpipes 16 and the branches 8.

In certain types of construction it is possible that the addition of theexhaust manifold of my invention may interfere with the application andremoval of the materialof cowl structure. To obviate this difficulty theconstruction indicated in Figure 5 may be used. In this embodiment thecowl 10 of Figures l and 2 may be cut into portions. For instance, anose portion 26 may be provided,

.cooperating with a recess portion 27 in the recess of which the exhaustmanifold 15 may be positioned. The manifold may be spaced 13o vficationsas are away from the member 27 by a small distance as before to providethe passageway 20 for cooling air. This-construction permits the readyremoval of the nose portion of the cowl for access to the enginemembers, or of the rear portion, or of the manifold and grooved portiontogether.

As a further modification the cowl member may be separated at two pointsas shown in Figure 5 to provide a nose portion 26, a channel portion 27and a rear portion 28. This construction permits the removal of the noseportion and the rear portion of the cowl independently of the exhaustmanifold and of the recess portion. This modification of theconstruction provides means for a more convenient and easy access to theengine structures.

It will be seen that a manifold structure and a method of mounting thesame have been provided which overcomes or obviates the air resistanceeffects which are ordinarily encountered in the use of a manifoldstructure which must be disposed transversely to the line of flight ofthe airplane on which it is carried.

The language and expressions which have been employe throughout thespecification are used as terms of description only and not oflimitation, andv such terms are intended to include all the equivalentsand such modipossible to be employed within the scope of the inventionclaimed.

I claim:

In an airplane having an engine and propeller at its forward end, astream lined cowl for enclosing the major part of said engine, said cowlhaving a circumscribing groove formed in its surface between said engineand propeller, and a stream lined exhaust manifold nested within saidgroove, spaced therefrom and formed so that its outer surface forms faceof said cowl, said manifold having its forward edge projecting slightlyoutside the surface of said cowl so as to deflect an air current intothe space between said cowl and said manifold.

In testimony whereof I aflix my si GIU ature.

SEPPE M. BELLA CA.

a substantial continuation of the sur-

